Mainstream party offerings Hillary Clinton and Donald Trump have proven controversial and unpopular. Poll after poll has shown voters were unsatisfied and willing to consider another option. Making sure to stress these facts constantly, Johnson presented himself as the most plausible alternative.

But Johnson hasn't caught fire -- a CNN/ORC poll found a third of likely voters said they did not know who he was -- and now an embarrassing moment on live TV could be his ultimate downfall.

"If it is kissing my chances goodbye, so be it," Johnson told Fox News' Neil Cavuto of the incident.

Johnson's day began on MSNBC's "Morning Joe," where the Libertarian was about what he would do to resolve the crisis in Aleppo, a Syrian city at the heart of the nation's civil war. Johnson responded, "What is Aleppo?"

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The questioner, Mike Barnicle, said, "You're kidding." And Johnson confirmed, no, he was not kidding.

The gaffe was instant fodder for cable news and a hit online. It signaled a weakness for Johnson on foreign policy and underscored the perceived novelty of his campaign. Moreover, it came as the race has briefly focused on national security.

Johnson released a mea culpa later in the day in the form of a statement, admitting, "I blanked."

Later in the morning, he appeared on ABC's "The View."

One of the questions: "If someone had a gun to your head would you vote for Hillary or Trump?"

"I would let it go off," Johnson responded.

Asked about being a possible Ralph Nader-like spoiler, Johnson said, "Well, I genuinely believe that I have the opportunity to win at this point."

National support lagging

Johnson and allied Libertarian groups have have stepped up their efforts, fundraising and ad purchases. But as of yet, his breakout has failed to materialize.

His polling is all over the place. The latest CNN/ORC poll found Johnson and his running mate Bill Weld securing 7% support among likely voters. But a Quinnipiac University poll of swing states released Thursday has him at 15% in North Carolina and 14% in Ohio. He was also clearly a factor in Florida, where Donald Trump and Hillary Clinton were tied at 43% and Johnson commanded 8% of likely voters.

In the face of recent polling, Johnson campaign spokesperson Joe Hunter told CNN the campaign would try to get into Ohio and North Carolina, but said there would be no change in strategy for the campaign in the face of the "Aleppo" comment.

Those state numbers are enough to have a major impact on the election between Clinton and Trump, but he needs 15% nationally to qualify for the presidential debates beginning later this month.

This is a relatively large increase from his position in 2012, when Johnson first ran for president and captured about 1% of the popular vote, but it is a far cry from anything approaching viability.

The Commission on Presidential Debates -- which Johnson, along with Green Party nominee Jill Stein, sued -- has an established threshold of 15% support among an average of five national polls to qualify for the debates. Johnson made clear from the outset his goal was to secure an invitation.

Asked by Fox News' Chris Wallace in late August about what exclusion from the debates would mean, Johnson said, "I would say game over."

The first debate is September 26, the cutoff point for the qualifying period is looming and short of a stunning upset, Johnson will not be on the stage.

CNN's Political Prediction Market, a game in partnership with a company called Pivit that uses polls, player input and other factors to predict where the election will go, has also indicated dwindling chances for Johnson.

The market's assessment of any third party candidate's chances of making the debate stage has cratered over the past few weeks, dropping from 48% to about 3% as of mid-Thursday.

Republicans aren't flocking

Johnson failed to break out from obscurity when he ran for president in 2012. But when he accepted his party's nomination in May, he said this time was going to be different.

Outside of the contempt many people had for Trump and Clinton, Johnson would have Weld, a former Massachusetts governor, at his side. He pitched Weld as more than a running mate, but essentially an equal and said they planned to form a "co-presidency" should he win the White House. Though this seemed to have been bourne out of Johnson's genuine admiration for Weld, it also lent seriousness to his candidacy.

Weld had once been a significant Republican fundraiser and had a connection to a man who had followed in his footsteps, former Massachusetts Gov. Mitt Romney, the 2012 Republican presidential nominee.

Romney has been perhaps the most outspoken voice within the Republican Party against Trump, and his endorsement could have been a major boon to the Johnson/Weld ticket.

But his endorsement never came. He told CNN's Wolf Blitzer in June that he would have supported Weld for president, but that he didn't know enough about Johnson and was turned off by his former third-party challenger's enthusiasm for marijuana legalization.

Johnson said he eventually spoke with Romney, and in August said he did not expect Romney's support.

Romney did come through for the ticket at least once, however. In a tweet on Tuesday, Romney said he hoped Johnson and Weld would get to join the national debates.

I hope voters get to see former GOP Governors Gary Johnson and Bill Weld on the debate stages this fall.